Clean up mapped partitions in docker on macOS

Docker containers running in Docker Desktop for Mac appear to have a
version of `kpartx` that doesn't properly clean up mapped partitions
upon execution of `kpartx -dsv`.

To work around this behaviour, the kpartx_plugin now unmaps mapped
partitions as required using `dmsetup remove <part>`, and frees the
loopback device using `losetup -d <device>`

This change requires the list of partition mounpoints to be an ordered
list in order to be able to unmap mapped partitions in the correct
order, so `Tags.get_tags()` has been updated to return the ordered list
`self._tagnames` instead of `self._tags.keys()` which (for Python
versions before 3.7) returns an unorderd list.

2 files changed, 17 insertions, 2 deletions

diff --git a/vmdb/plugins/kpartx_plugin.py b/vmdb/plugins/kpartx_plugin.py
index 6303552..7c31cfc 100644
--- a/vmdb/plugins/kpartx_plugin.py
+++ b/vmdb/plugins/kpartx_plugin.py
@@ -14,7 +14,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # =*= License: GPL-3+ =*=
-
+import os
+import re
 
 import vmdb
 
@@ -47,3 +48,17 @@ class KpartxStepRunner(vmdb.StepRunnerInterface):
     def teardown(self, values, settings, state):
         device = values["kpartx"]
         vmdb.runcmd(["kpartx", "-dsv", device])
+        # docker containers on macOS don't honor the kpartx cleanup command, so
+        # we have to do the clean up ourselves... :-/
+        loop_devs = set()
+        for tag in state.tags.get_tags():
+            dev = state.tags.get_dev(tag)
+            m = re.match(r"^/dev/mapper/(?P<loop>.*)p\d+$", dev)
+            if m is not None:
+                if os.path.exists(dev):
+                    vmdb.runcmd(["dmsetup", "-v", "remove", dev])
+                loop = m.group("loop")
+                loop_devs.add("/dev/{}".format(loop))
+
+        for loop_dev in loop_devs:
+            vmdb.runcmd(["losetup", "-d", loop_dev])
diff --git a/vmdb/tags.py b/vmdb/tags.py
index 818193f..0e59f1a 100644
--- a/vmdb/tags.py
+++ b/vmdb/tags.py
@@ -25,7 +25,7 @@ class Tags:
         return repr({"tags": self._tags, "tagnames": self._tagnames})
 
     def get_tags(self):
-        return list(self._tags.keys())
+        return self._tagnames
 
     def has_tag(self, tag):
         return tag in self._tags